INTRODUCTION - Building in California · INTRODUCTION 2005 Worldwide PV Production 1,565 megawatts...

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Program Funded By:

Sacramento Municipal

Utility District

&

California Solar Energy

Industries Association

Instructional Design By:

Rodney Slaughter

Technical Review

Dirk Drossel, Fire InspectorBurbank Fire Department

Howard Cooke, Fire InspectorSacramento Fire Department

Russ Tingley, Fire ChiefHermosa BeachFire Department

Bob Gill, Chief Central Calaveras

County Fire & Rescue

Scott Corrin, Fire MarshalU.C. Riverside Fire Department

Lee Parker, CaptainModesto Fire Department

Sue Kateley California Energy Commission

Les NelsonCAL SEIA

Jon BertolinoSacramento Municipal Utilities District

INTRODUCTION

Program Goal:

To provide fire service personnel with an

awareness of photovoltaic systems, so that

you can make informed decisions and

operate safely during an emergency.

INTRODUCTION

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Course Materials on Compact Disk:

• Student Manual

• Student Handout

• Instructor Guide

• Powerpoint Presentation

INTRODUCTION

Student Introductions

• Name

• Rank/Position

• Department or Agency

• What do you know about solar energy?

• What do you hope to learn?

INTRODUCTION

AGENDA

INTRODUCTION

CELLS AND COMPONENTS

PV PERFORMANCE

PV APPLICATIONS

CODES AND STANDARDS

EMERGENCY RESPONSE

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What are the chances of responding to an emergency where a photovoltaic system

has been installed?

INTRODUCTION

2005 Worldwide PV Production1,565 megawatts

2005 Worldwide PV Production:Germany at 53% or 837 MWJapan at 14% or 292 MWU.S.A. at 3% or 104 MW

By 2010, 2.5 gigawatts of PVproduction is projected worldwide

INTRODUCTION

California is the National leader 17,300 grid-connected systems

California’s Goal:One million solar roofs by 2017

Generating 3,000 MW of electricity

Double the worldwide PV output in 2005

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INTRODUCTION

Livermore, California – Multi-family housing development outfitted with PV electric systems- the wave of the future!

Are photovoltaic systems

safe to operate around?

INTRODUCTION

Yes! Under normal operating conditions

The PV industry has a good safety record

But, no technology is risk free!

Only one recorded PV electrical injury to afire fighter was reported worldwide

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INTRODUCTION

Emergency ConditionsKnow the Potential Hazards:

Electric Shock

Inhalation Exposure

Falls from Roofs

Roof Collapse

INTRODUCTION

With a concentration of PV in San Diego, there were no reported injuries during the 2003 wild fires

SUMMARY

The fire service has been known to be resistant to technological changes in our society.

Alternative energy production is the next big technological change that the fire service will

have to come to terms with.

SMUD and CAL SEIA have seen the need to inform emergency responders of how to work

around photovoltaic technology safely.

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AGENDA

INTRODUCTION


PV PERFORMANCE

PV APPLICATIONS

CODES AND STANDARDS

EMERGENCY RESPONSE

”Give me the splendid silent sun with all its beams full-dazzling.”Walt Whitman, 1865

OBJECTIVE

To recall the principles of photovoltaics

To identify the components of a photovoltaic system

SOLAR FACTS

One day of sunshine could supply all the world’s energy for 4 to 5 years

The Sun’s full intensity and brightness is 1,000 watts per meter squared (referred to as insolation)

This intensity can be diminished according to the micro climate and site specific conditions (shade)

PV CELLS & COMPONENTS

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SOLAR FACTS

In the Northern Hemisphere, most photovoltaic systems are orientated towards true south to maximize the amount of light falling on the photovoltaic panels

Peak sun per day is about 5 hours, between 10 am and 3 pm (peak energy production)


Anatomy of a Solar Cell

The solar cell is the smallest unit of the PV system

There are two types of manufactured PV’s:

•Silicon cell or•Amorphous silicon

PV cell has a thin layer of silicon 1/100th of an inch

Silicon is layered with other materials to create the photoelectric reaction


Anatomy of a Solar Cell

Boron is used for the positive layer

Phosphorus is used for the negative layer

Photons generated from the sun energize and knock loose the extra phosphorus electron which crosses the P/N junction to fill the hole on the boron atom

The energy released in the process produces .5 volt of direct current (DC)


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The Photovoltaic Effect


Phosphorus -Boron +

MANUFACTURING PROCESSES

The purest silicon structure comes from thegrowth of a single crystal, monocrystalline,cut in to thin wafers

Multiple crystals cast together and sliced intothin wafers form polycrystalline structures

A chemical process that deposits silicon on asubstrate material like glass or stainless steel as a thin film is referred to as amorphous


MANUFACTURING PROCESSES

To improve PV efficiency and reduce cost, the industry is using materials such as cadmium telluride and gallium arsenide

Toxic and hazardous chemicals are usedin the PV manufacturing process

When a module is exposed to fire or an explosion, trace chemicals can be released into the atmosphere


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Monocrystalline

Modules have output capacities of 14 to 15%

Monocrystalline achieves the highest efficiency in electric energy production

Its production cost is higher than other silicon types


Polycrystalline

Pure molten silicon is cast into molds, then sliced into wafers, doped and assembled


Installation of polycrystalline

modules on a rack system.

Polycrystalline is lower in conversion efficiency compared to Monocrystalline, averaging about 12 to 14% output capacity

Amorphous

Made by vaporizing silicon and depositing it on a glass, steel or flexible surface

Some are flexible and are able to be rolled and used for remote electricity generation

The flexibility of amorphous technology allows it to be used in a wider range of applications


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A semitransparent amorphous silicon product used as a gas station canopy in Fairfield, California

Top - looking down on the canopy

Bottom – looking up through the canopy

Amorphous

Production costs less than other production techniques, but the output capacity, is reduced to 5 to 7%

A square foot of amorphous siliconaverages about 5 watts, monocrystalline or polycrystalline average about 10 watts per square foot


The Photovoltaic System Includes

Modules/Array (Tiles or Shingles)

Optional Batteries

Battery Controller

Inverter

Mounting Systems


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Photovoltaic Modules

PV cells connected in series and parallel –the voltage and amperage is accumulated to achieve the desired electrical output

Photovoltaic cells connectedtogether form a PV module

Weather-proof electrical connectionsconnect modules together

In rare occasions junction boxes can overheat and can lead to roof damage and potential fire


Photovoltaic Modules

Modules have a variety of sizes and rated output, with the standard size module at 24-volts, consisting of 72 solar cells

An average size crystalline module weighs between 30 and 35 pounds

Photovoltaic panels have no moving parts andrequire little maintenance


Photovoltaic Array

Two or more modules connectedtogether form a photovoltaic array

Residential system outputs of600 volts are not uncommon

The average household in California uses about 6,500 kilowatt-hours per year


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Photovoltaic ArrayThe modules wired together in series to accumulate voltage, and the strings are wired together in parallel to Increase amperage, collectively they form the array

Array in Series and Parallel


Photovoltaic Array

A PV system in the 3 to 4 kilowatt range would meet most homeowner’s electricity needs

A 30 module array would operate at over 4,000 watts and weigh approximately 900to 1,050 pounds

This weight spread equally over a 420 square foot area of the roof would result in a roof weight load of 2.5 pounds per square foot


Photovoltaic Tiles and Shingles

PV tiles or shingles can be integratedinto the home’s roof covering

It takes more time, wiring individualtiles or shingles together

PV tile or shingle roofing systemis less obtrusive but costs more

In High Fire Hazard Severity Zones, roofing systems must meet Class A of Title 24 CCR


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Photovoltaic Tiles and Shingles


Manufacturers of PV shingles haveachieved a Class A rating by usinga fire resistant underlayment beneath the PV shingles

Some manufacturers of PV roofing tiles have tested their products and meet the standard for Class A roofing

Batteries

Lead acid batteries are used to store PV-generated electricity

Batteries are used in off-grid PV systems, although battery back-up can be used ingrid-connected applications

Without batteries, a grid-tied PV system cannot provide PV electricity when the utilitygrid is not energized


Batteries


Pinnacles National Monument in California installed a 9.6-kilowatt photovoltaic system. It eliminates the fuel bill for a diesel generator that produced 143 tons of carbon.

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Batteries

A battery is an electrochemical cell

The electrical potential between thepositive and negative electrodes is about 2 volts direct current (DC)

The battery can off-gas oxygen from the positive electrode and hydrogen from the negative electrode

Escaping gases are highly flammable, sparks and open flames are not allowed near the batteries


Batteries


Like the PV modules, batteries are wired in series and parallel to provide the voltage and amperage necessary for the operation of the electrical system

Battery Charge Controllers

To keep battery charge levels in check, a charge controller is used in the PV system

The battery charge controller prevents overcharging reducing the danger of off-gassing

Many controllers also protect the battery fromover-discharges as well


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Battery Charge Controllers


Battery charge controllers are found in off-grid systems

and grid-tied systems that have a battery back-up.

PV Inverters

The PV array, batteries and charge controllers all function on direct current (dc)

Most household appliances run on alternating current (ac)

The inverter changes the direct current to alternating current at 60 hz


PV Inverter


This sine wave inverter is used on a grid-tied system.

A look inside an inverter during the installation process.

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PV Inverters

There are three types of inverters; square wave, modified square wave and sine wave

Sine wave inverters produce a high quality waveform used to operate sensitive electrical equipment

Sine wave inverters are required for grid-tied PV systems

Grid-tied inverters are designed to shut down when there is no grid power


Mounting Systems


PV modules can be mounted directly on the roof, in many cases specialized roof racks lift the array from the roof deck allowing air to circulate under the modules.

Many PV systems are designed to withstand 80 mile per hour winds.

Mounting Systems


PV systems can also be mounted on the ground using customized racks, or they can be mounted on poles.

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Other Solar Technologies


The long rectangular panel at the bottom of this array is a solar water heating panel.

Solar thermal panels (solar water heating collectors) are used to heat water for the swimming pool or for domestic hot water

Two solar hot water panels are on the left of this roof and 44 modules of this 7 kw PV array on the right of this 3,000 sq. ft. home. The system is backed-up with a generator.

Other Solar Technologies

Skylights are a function of passive solar design, allowing natural light to enter the interior of the building


A skylight with integrated photovoltaic will have a distinctive amorphous rectangular pattern in the glass


PV panels are Distinctive: making

them relatively easy to recognize

when you know whatto look for!

Photovoltaic Identification

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SUMMARYThe greatest danger for emergency responders

is the lack of PV knowledge needed to safelyoperate around this emerging technology

This section provided you with anintroduction to the photovoltaic system

Identification of the PV array and all the related components is critical in an emergency response

AGENDA

INTRODUCTION


PV PERFORMANCE

PV APPLICATIONS

CODES AND STANDARDS

EMERGENCY RESPONSE

“Is it fact, or have I dreamt it—that, by means of electricity, the world of matter has become a great nerve, vibrating thousands of

miles in a breathless point in time.”Nathaniel Hawthorne, The House of the Seven Gables, 1851

Objective

To cite historical milestones in the development of PV’s

To recall the factors that effect PV performance

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PV PERFORMANCEPV Historical Brief

Bell Labs developed the silicon photovoltaic (PV) cell1954

Vanguard I space satellite used a small array to power radios1958

Polish scientist developed a way to grow single-crystal silicon1918

Einstein published his paper on the photoelectric effect1905

Discovered selenium produces electricity when exposed to light1876

Will Smith discovered the photoconductivity of selenium1873

French scientist discovers the photovoltaic effect1839

PV PERFORMANCEPV Historical Brief

SMUD commissions its first 1-megawatt PV facility1984

Cumulative worldwide PV capacity reaches 1000 megawatts1999

Arco Solar dedicates a 120 acre 6-MW PV substation1983

Worldwide photovoltaic production exceeds 9.3 megawatts1982

One megawatt power station goes on-line in Hisperia, California1982

NASA launches satellite powered by a 470-watt PV array1964

Bell Telephone Laboratories launches the first telecom satellite1962

PV Performance

Limitations on technology: PV only converts as much as 20% of the suns energy

Environmental factors: overcast days caused byclouds and smog can lower system efficiency

Shade: chimneys, trees and nearby buildings shade panels and reduce the output for the entire array

Temperature: PV systems operate best at 90 degrees or lower

PV PERFORMANCE

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PV Performance

Site Specific: availability of sunshine throughout the year, including average daily insolation, site latitude, magnetic declination (true south), tilt angle and site specific information such as local weather and climate

Design: Installers underestimate the rated PV module output by 15 to 25% from the manufacturers tested output, some energy is lost as heat in the DC-AC conversion

PV PERFORMANCE

PV Concepts

Voltage is the measure of electrical potential between two points

Amperage is the rate at which the electrons flow through the circuit.

Wattage is the rate an appliance uses electrical energy, or rather the amount of work done when one amp at one volt flows through one ohm of resistance

PV PERFORMANCE

PV Concepts

Ohm’s Law is a mathematical equationto calculate the value of these terms

The Ohm’s formula is:Volts x Amps = Watts

You can flip this equation around to find other values

Watts ÷ Amps = Voltsor

Watts ÷Volts = Amps

PV PERFORMANCE

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PV Concepts

Ohm’s formula is used to calculateenergy demand and for PV design

Watt-hour measures energy being used

One thousand watts consumed over the periodof one hour is one kilowatt hour, (or kWh)

Installers will analyze the energyusage and customer expectations

Energy conservation plays a significant rolein PV performance and customer satisfaction

PV PERFORMANCE

SUMMARYThe physics of electricity never change,

regardless of how the electricity is generated.

There are a number of factors that affect overall PV

system performance including the technology itself.

Recognizing these factors is another key to personnel

safety when working around PV systems.

AGENDA

INTRODUCTION


PV PERFORMANCE

PV APPLICATIONS

CODES AND STANDARDS

EMERGENCY RESPONSE

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“The world we live in is but thickened light.”Ralph Waldo Emerson, The Scholar,1883

ObjectiveTo identify PV applications and

the components associatedwith each application

PV APPLICATIONS

In December of 1998

Astronauts Jerry L. Ross (left)

and James H. Newman work

together on the final of three

space walks of the STS-88

mission. (Photo Credit: NASA)

Even if you don’t use PV directly you are doing so indirectly.

Communication systems and satellites with integrated PV systems provide power that improves the efficiency of our everyday liveseven though you may not be aware of it!

PV APPLICATIONS

Landscape lightingPumps

TelecommunicationBlowers

FlashlightsFans

RadiosToys

WatchesCalculators

Integrated with Battery Back-Up

Day Use

These are some of the common applications

of PV that you are already familiar with

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PV APPLICATIONS

Direct Current (DC) Systems

Components in a directcurrent system include:

Photovoltaic module or array

Battery charge controller

Batteries and

Direct current appliances

PV APPLICATIONS

DC to AC Systems

In rural areas, people can power their homes by converting the direct current (DC) generated from the PV system to alternating current (AC)

This PV system includes:

Solar Modules or ArrayBattery ControllerBatteriesPlus an Inverter

PV APPLICATIONS

DC to AC SystemsThis PV system includes:


This battery charge controller monitors the energy

level in the battery as it charges and discharges

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PV APPLICATIONS

This PV system includes:


DC to AC Systems

Battery backed-up PV systems provide electricity for a specific period of time without sunshine

PV APPLICATIONS

DC to AC SystemsThis PV system includes:


These inverters convert direct current from the PV array and battery bank to alternating current

PV APPLICATIONS

Grid–Tied System

This system allows

the building owner to

generate and use PV

power during the day

and deliver excess

power directly to the

utility grid

This PV system includes: Solar Array & Inverter

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PV APPLICATIONS

Grid–Tied System

To insure that the inverter is disconnected once the main electrical panel is locked out, fire personnel can also use the manual disconnect next to the inverter as an extra precaution

Line-in from the array In this system the

utility grid provides

the back-up power

and eliminates the

need for batteries

in the system

PV APPLICATIONS

Grid–Tied System

In this application where the inverter and main electrical panel is a distance from the meter another disconnect has been installed behind the meter on the utility pole

Loss of power from the

grid will disconnect

electricity in the building

including the ability to use

the electricity generated

by the PV system

PV APPLICATIONS

You may not be able to see a PV system on a flat roofed building from street level. The large inverters at the USPS processing and distribution center in Marina Del Rey, would be your first clue of the existence of a 127 kw monocrystalline PV system on the roof.

Grid–Tied System

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PV APPLICATIONS

BUILDING INTEGRATED DESIGN

The developing trend is to incorporate PV systems seamlessly into the building’s exterior finish and landscape design

Laminated to the skylight glass are photovoltaic cells that produce electricity as well as serve as an element in the shading and day lighting design at the Thoreau Center for Sustainability, Presidio National Park, San Francisco, California.

PV APPLICATIONS

BUILDING INTEGRATED DESIGN (BID)

BID systems appear as PV roofing systems, windows, skylights or patio covers

PV canopies at CAL EXPO in Sacramento provide shade to parked cars

PV APPLICATIONS

BUILDING INTEGRATED DESIGN

Blending this technology into

traditional building and

landscape design is one of the

many challenges designers are

involved in and presents new

challenges for emergency

responders in identifying PV

technology when sizing-up an

emergency

The solar cube stands 135 feet tall on top of the

Discovery Science Center in Santa Ana, CA

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SUMMARYPV is used in a wide range of applications were

electricity is needed; from simple and inexpensive appliances to high end satellites.

The future trend will be to integrate PV seamlessly and unobtrusively into buildings and building sites.

This trend will make PV system identification a little more challenging for emergency responders.

AGENDA

INTRODUCTION


PV PERFORMANCE

PV APPLICATIONS

CODES AND STANDARDS

EMERGENCY RESPONSE

“Progress imposes not only new possibilities for the future but new restrictions.”Norbert Weiner, The Human Use of Human Beings, 1954

Objective

To reference codes and standards as they relate to personnel safety and photovoltaic systems

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Direct current photovoltaic conductor (wiring) is runoutside a building membrane in metallic conduit

CODES & STANDARDS

Wiring Identification

National Electric Code specifies that conductors of different output systems will be contained in separate raceways, cable trays, cable, outlet box, junction box, or similar fittings

System Disconnects

The Uniform Fire Code specifies that the disconnecting means is accessible to the fire department

In this system the inverter is flanked by two disconnects the right disconnects the array and the left disconnects the inverter from the main electrical panel

CODES & STANDARDS

System Disconnects

NEC requirements provides the detail for disconnecting all components and conductors in the system

Disconnects can be located next to the meter, main electrical panel, the inverter, the controller, and the battery bank

Each PV disconnect shall be permanently marked to identify it as a photovoltaic system disconnect

CODES & STANDARDS

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System Disconnect and Warning Labels

CODES & STANDARDS

System Disconnects

Importantly, a grid-tied PV system can operate as a stand-alone system to supply loads that have been disconnected from electrical production and distribution network sources

You would find this arrangement in grid-tied systems in a battery back-up or generatorback-up system

CODES & STANDARDS

Low voltage DC systems often have larger wiring sizes compared to AC systems

The circuit conductors and overcurrent devices are sized to carry not less than 125 percent of the maximum calculated currents

Wiring exposed to the weather must berated and labeled for outdoor use

To reduce fire hazards, roof mounted PV systems, conductors, and components areall required to be grounded

Wiring (Conductors)

CODES & STANDARDS

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Specific requirements are listed in the NEC for providing ground fault protection for PV systemsand components

Labels and markings applied near the ground-fault indicator at a visible location, stating that, if a ground fault is indicated, the normally grounded conductors may be energized and ungrounded

In one- and two-family dwellings, live parts in photovoltaic source circuits and photovoltaic output circuits over 150 volts to ground shall not be accessible to other than qualified persons while energized

Ground Fault Protection

CODES & STANDARDS

Locating the grounding connection point as close as practical to the photovoltaic source better protects the system from voltage surges due to lightning

Ground Fault Protection

Exposed non–current-carrying metal parts of module frames, equipment, and conductor enclosures shall be grounded regardless of voltage

Installer connecting ground wire to module frames.

CODES & STANDARDS

In a PV module, the maximum system voltage is calculated and corrected for the lowest expected ambient temperature

PV Modules

This voltage is used to determine the voltage rating of cables, disconnects, overcurrent devices, and other equipment

CODES & STANDARDS

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In one and two-family dwellings, photovoltaic source circuits and photovoltaic output circuits are permitted to have a maximum photovoltaic system voltage of up to 600 volts

Installations with a maximum photovoltaic system voltage over 600 volts shall comply with Article 490

PV Modules

CODES & STANDARDS

A label for the photovoltaic power source will be provided at an accessible location at the disconnecting means for the power source providing information on:

Operating currentOperating voltageMaximum system voltageShort-circuit current

PV Modules

The rated capacity of the module is provided on the back of each panel

CODES & STANDARDS

Storage batteries in a photovoltaic system should be installed in accordance with the provisions of NEC Article 480

Storage batteries for dwellings will have the cells connected to operate at less than 50 volts nominal

Lead-acid storage batteries for dwellings shall have no more than twenty-four 2-volt cells connected in series (48-volts nominal)

PV Batteries

CODES & STANDARDS

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Flooded, vented, lead-acid batteries with more than twenty-four 2-volt cells connected in series (48 volts, nominal) shall not use conductive cases or shall not be installed in conductive cases

Conductive racks used to support the nonconductive cases shall be permitted where no rack material is located within 150 mm (6 in.) of the tops of the nonconductive cases

Some batteries do require steel cases for proper operation as these battery types such VRLA or nickel cadmium can experience thermal failure when overcharged

PV Batteries

CODES & STANDARDS

Chapter 52, NFPA 1, Uniform Fire Code (2006)

Valve-regulated lead–acid (VRLA) battery systems should have a listed device or other approved method to preclude, detect, and control thermal runaway

Provide an approved method and materialfor the control of a spill of electrolyte

Provide ventilation for rooms and cabinetsin accordance with the mechanical code

PV Batteries

CODES & STANDARDS

Chapter 52, NFPA 1, Uniform Fire Code (2006)

Provide signs on rooms and cabinetsthat contains lead–acid battery systems

In seismically active areas, battery systems shall be seismically braced in accordance with the building code

PV Batteries

CODES & STANDARDS

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During plan review ensure that there is adequate access to the roof for firefighting operations

Fire Inspectors need to stay involvedin the permit and plan review process

Pass available building and PV information onto the operational section of your department

Firefighters need to take this information anddevelop pre-emergency plans for these facilities

Fire Service Responsibilities

CODES & STANDARDS

SUMMARY

Automatic and manual disconnects throughout the PV systemallow firefighters to contain the electricity at the source

Firefighters have successfully dealt with leadacid batteries and battery systems for decades

The Building, Electrical, and Fire Codes ensurethe safety for occupants and emergency responders

AGENDA

INTRODUCTION


PV PERFORMANCE

PV APPLICATIONS

CODES AND STANDARDS

EMERGENCY RESPONSE

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“We are here to make a choice between the quick and the dead”Bernard Baruch, U.N. Atomic Energy Commission, 1946

ObjectiveTo identify and mitigate potential hazards whileworking around PV at the site of an emergency

To use this information to develop a standardoperating guideline for your department

EMERGENCY RESPONSE

Fire Fighter Hazards

Inhalation Exposure Hazards

Electrical Shock & Burns

Falls from Roof Operations

Roof Collapse

Batteries

Emergency ResponseHow do you work with PV

What not to do around PV

EMERGENCY RESPONSE

Inhalation Hazards

During a fire or explosion

the PV frame can quickly

degrade exposing hazardous

chemicals to direct flame and

become dissipated in the

smoke plume

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EMERGENCY RESPONSE

Inhalation Hazards

Boron- No health effects to humans or the environment

Cadmium Telluride- A known carcinogen, the primary route of exposure is inhalation

Gallium Arsenide- The health effects have not been studied, it is considered highly toxic and carcinogenic

Phosphorus- The fumes from compounds are considered highly toxic. NIOSH recommended exposure limit to phosphorus is 5 mg/m3. A lethal dose of phosphorus is 50 milligrams

EMERGENCY RESPONSE

Inhalation Hazards

Recommended Practice:

• Wear SCBA and full protective clothing

• Shelter-in-place populations-at-risk downwind of fire

EMERGENCY RESPONSE

Electric HazardsNIOSH reports reveal the number of firefighters who

are killed and injured annually in electrical incidents

Electricity can cause a variety of effects, ranging

from a slight tingling sensation, from involuntary

muscle reaction to burns and death!

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EMERGENCY RESPONSE

Electric Hazards

The physiological effects produced by electricity flowing through the body include:

Perception – (1 mA) tingling sensation

Startle Reaction – (5 mA) involuntary muscle reaction

Muscle Tetanization – (6 to 30 mA) painful shock

Respiratory Arrest – (.5 to 1.50 Amps) stop breathing

Ventricular Fibrillation – (1 to 4.3 Amps) heart stops

EMERGENCY RESPONSE

Electric Hazards

Variables in human resistance to electricity:

Amount of current flowing through the body

Path of current through the body

Length of time the body is in the current

Other Factors: Body size and shape, Area of contact, Pressure of contact, Moisture of contacts, Clothing & jewelry, Type of skin

EMERGENCY RESPONSE

Electric BurnsBurns that can occur in electrical accidents include electrical, arc, and thermal

With electrical burns, tissue damage occurs because the body is unable to dissipate the heat from the current flow

Temperatures generated by an electric arc can melt nearby material, vaporize metal in close vicinity, burn flesh and ignite clothing at distances of up to 10 feet

Arc temperatures can reach 15,000 to 35,000 degrees

A firefighter should never pull the electrical meter as a means of shutting-down power to a building!

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EMERGENCY RESPONSE

Roof Hazards

To cut ventilation, select a spot at the highest point of the roof and as close to the fire as possible

Do not cut into PV modules!

Consider cross ventilation?

In roof operations consider the weight of the PV array on aweakening roof structure and the fact that you may not be able to access the roof over the fire

Roof vents, skylights, solar thermal panels, and PV array pose a trip hazard to fire fighters conducting roof operations

EMERGENCY RESPONSE

Battery Hazards

As a rule, batteries do not burn; or rather, they burn with great difficulty

If batteries are exposed to fire, however, the fumes and gases generated are extremely corrosive

Spilled electrolyte can react and produce toxic fumes and release flammable and explosive gases when it comes into contact with other metals

Due to the potential of explosive gases, prevent all open flames and avoid creating sparks

EMERGENCY RESPONSE

Battery Hazards

In battery emergencies, wear full protective clothing and SCBA on positive pressure

Extinguish lead-acid battery fires with CO2, foam or dry chemical fire extinguishers

Do not use water!

Never cut into the batteries under any circumstances!

If the battery is punctured by a conductive object, assume that the object has electrical potential

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EMERGENCY RESPONSE

Personal Protective EquipmentFirefighters should follow the minimum standard in NFPA 1971, Protective Ensemble for Structural Firefighting and NFPA 1500, Chapter 7 Personal Protective Equipment

This would include:Turnout pantsTurnout coatBootsGlovesHoodHelmetSCBA

Note: Jewelry such as; watches, rings, and necklaces are all a good conductor of electricity and should not be worn around electrical components

EMERGENCY RESPONSE

Personal Protective Equipment

When working in proximity to electrical circuits, use insulated hand tools

To check for electricity flowing between two contacts an AC/DC meter should be employed

Typically, hot sticks on many engines can only detect alternating current and would not detect curent in PV wiring or battery conductors

EMERGENCY RESPONSE

Emergency Operations

Size-Up – the roof and look for warning labels on electrical disconnects

Lock-Out & Tag-Out - all electrical disconnects,isolating the PV system at the inverter

Ventilation - consider where to cut or whether to use cross ventilation

Shelter-in-Place – Does the size of the emergency and the involvement of the array constitute the need to protect populations downwind?

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EMERGENCY RESPONSE

Emergency OperationsThe PV array will always generate electricity when the sun shines- there is no turning it off!

Walking or breaking PV modules could release all the energy inherent in the system simultaneously

Cut or damaged wires from a nighttime operation could become energized in the day-time

Spotlights during an evening operation is not bright enough for the PV system to generate electricity

Lightening is bright enough to create electrical surge!

EMERGENCY RESPONSE

Emergency Operations

You cannot block all the sunlight on the array with foam or a salvage cover

Foam will not block out all the sunlight and will slide off the array

Salvage cover will significantly reduce sunlight to the array but electricity can still be generated through the material of the salvage cover

EMERGENCY RESPONSE

Emergency OperationsLocate battery storage area (if applicable)

Extinguish lead-acid battery fires with CO2,foam or dry chemical fire extinguishers

Use Class C extinguishing agents- CO2 or dry chemical if a PV system shorts and starts a fire

Should the array become engulfed in a roof fire, use water in a fog pattern on the PV array

Be aware that biting and stinging insects could inhabit the module frame and junction boxes

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SUMMARYPhotovoltaic technology is around you every day

and it is here to stay!

Your fundamental understanding of photovoltaic systems will improve your confidence in working

with and around solar technology safely.

The photovoltaic industry is counting on the fire service industry to operate safely and effectively

around photovoltaic systems.

INTRODUCTION - Building in California · INTRODUCTION 2005 Worldwide PV Production 1,565 megawatts...

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Transcript of INTRODUCTION - Building in California · INTRODUCTION 2005 Worldwide PV Production 1,565 megawatts...